SIGNS OF ILLNESS
A thriving neonatal puppy or kitten is warm, plump, vigorous, and hungry. Until age 4 to 7 days, a healthy neonate's mucous
membranes are hyperemic because of increased numbers of circulating erythrocytes.9 A normal packed cell volume for the first few days postpartum is around 60%.10
Most neonates that are apparently healthy at birth but decline in status have several features in common, regardless of the
cause of their illness. These animals are often suffering from one or more of the following conditions: hypoxemia, hypothermia,
dehydration, and hypoglycemia.3,11-14 They do not gain weight at the same rate as their littermates do (or, if the entire litter is affected, they do not gain
as much weight as is average for their breed or species). They are not active or searching for food, and they lack the normal
suckling and flexor reflexes. Dams will often isolate sick animals from the rest of the litter, exacerbating their problems.
Once it has been determined that a neonate needs veterinary care, treatment must be multifaceted and address each challenge
the neonate is facing in order to provide the best chance for full recovery. Once the critical stage has passed, further diagnostic
tests can be considered to determine the inciting cause.
POSTPARTUM NEONATAL RESUSCITATION
Ideally, parturition should be relatively uneventful and can be completed at a client's residence. However, veterinarians
will sometimes manage delivery in a clinical setting because of either a high-risk pregnancy expected to result in dystocia
or a planned cesarean section. Or problems may occur at home, and an owner may bring in the dam or newborn puppies or kittens
for evaluation. Thus, the veterinarian and clinic staff need to be prepared for examination and possible resuscitation of
one or more neonates.
Special care must be taken with handling and equipment to prevent nosocomial infection of the neonate. Wear gloves when handling
neonates, and sterilize equipment before and after contact with the neonate.
Hypoxia and hypothermia
(DIGITAL VISION/GETTY IMAGES)
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The main cause of fetal stress and depression associated with dystocia or cesarean section is hypoxia. Hypoxia can result
from physical blockage of the respiratory tract or umbilicus during dystocia when a neonate is trapped in the vaginal canal,
or from respiratory depression caused by anesthetic agents administered to the dam during surgery.15 In stark contrast to hypoxic adults, hypoxic neonates exhibit bradycardia, decreased respiratory rate, and reduced thoracic
wall movement.15
This is likely an autoregulatory response carried over from the fetal period into the first few weeks postnatally in order
to conserve energy and oxygen.15
Hypothermia also adversely affects neonatal physiological functions. Hypothermia leads to further bradycardia (in an attempt
to decrease metabolic demand),3
which worsens tissue hypoxia and leads to metabolic acidosis.1 Hypothermia is important to address in decompensating neonates (see "Hypothermia"). The shivering and vasoconstrictive responses are not present until about a week of age,13 normal adult central thermoregulation does not fully develop until 28 days of age,16 and neonates lack insulating fat.
If the dam is undergoing a cesarean section, the risk of neonatal hypothermia can be decreased by ensuring that the dam maintains
a normal body temperature throughout the surgery. Hypothermia of the dam can translate to hypothermia of the offspring, especially
in cats and small dogs that can dissipate body heat rapidly while anesthesitized.15
Keeping a newborn puppy or kitten at the ideal body temperature and stimulating the skin by rubbing it with a warm towel may
be enough to arouse a newborn neonate to have normal respirations,15
especially if the dam is still anesthetized and unable to care for the newborns. The normal respiration rate for a newborn
puppy or kitten is 10 to 18 breaths/min.8 If the animal is hypothermic, the respiration rate will be depressed.
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